<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title>随即点名</title>
	</head>
	<body>
		<script>
			var arr=new  Array('1a','2b','3c','4b');
			var a=parseInt(Math.random()*4)+1;
			alert(arr[a]);
		</script>
		
	</body>
</html>
